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Heading for Mars

StarDate:

October 10, 2013

When spring arrives in the southern hemisphere of Mars, dark streaks begin inching down some steep slopes that are close to the equator. As spring turns to summer, the streaks grow longer and turn darker. And when the weather turns cold, the streaks vanish — only to form again when spring returns.

There are several possible explanations for the streaks. The most intriguing is that they’re trickles of water from snow or frost that mix with salts in the Martian soil. That makes them possible places for future landers to look for evidence of microscopic life.

Researchers have seen the streaks only in photos from Mars-orbiting satellites. Yet they’re learning more about the streaks by digging into similar features right here on Earth — in the valleys of Antarctica.

In satellite photos, the streaks in Antarctica look just like those on Mars. They form when ice just below the surface melts in the summer heat. It percolates to the surface and flows downhill, dampening the soil and making the streaks darker.

Later this month, a team from the University of Texas Institute for Geophysics will head for Antarctica to study the streaks found in the McMurdo Dry Valleys. In particular, the scientists will look at what happens when the salty water in the streaks freezes. The studies should help them better understand the streaks on Mars — and whether they’re good places to hunt for life on the Red Planet.

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